With development of science and technique, intelligent terminals have more and more functions. For example, user's mobile phones have varied from traditional GSM and TDMA digital phones to intelligent phones capable of handling multimedia resources and providing multiple types of information services such as web browsing, telephone conference, e-business and etc. However, more variety of malicious code attacks for mobile phones and increasingly serious situation of personal data security problem has emerged accordingly. The users of intelligent mobile phone are suffering from increasing viruses for the mobile phone.
Protection technologies against malicious codes of mobile phone can defend against the malicious codes. The protection manners against malicious codes of mobile phone are diverse, for example, including feature value scanning, protection against malicious code based on virtual machine techniques, heuristic scanning and similar sample clustering. Regardless of the protections, except for the efficient scanning algorithm (also known as matching algorithm), it is elementary to organize an advisable malicious code feature library. Therefore, how to accurately and efficiently extract features would be essential for establishment of the feature library or even for the whole protection technologies.